18 animals in a pet store. some are birds and some are dogs. there are 50 legs in all. how many birds and how many dogs are there
A bird has only 2 legs, and a dog has 4 legs.
x=number of birds
y=number of dogs
We can susggest this system of equations:
x+y=18
2x+4y=50
We can solve this system of equations by substitution method.
x+y=18 ⇒ y=18-x
2x+4(18-x)=50
2x+72-4x=50
-2x=50-72
-2x=-22
x=-22/-2
x=11
y=18-x
y=18-11
y=7
Answer: we have 11 birds and 7 dogs.
Answer:
7 dogs and 11 birds
Step-by-step explanation:
18 animals in a pet store. some are birds and some are dogs. there are 50 legs in all.
We know that birds has 2 legs and dogs has 4 legs
Let 'b' be the number of birds
and 'd' be the number of dogs
Total animals = 18
\(b+d= 18\)
there are 50 legs in all. total legs = 50
\(2b+4d= 50\)
WE got two equations, now we solve for 'd'
Multiply the first equation by -2 to cancel out 'b'
\(b+d= 18\)
\(-2b-2d= -36\)
\(2b+4d= 50\)
--------------------------------------
\(2d= 14\)
Divide both sides by 2
d= 7
The number of dogs=7
\(b+d= 18\)
\(b+7= 18\)
Subtract 7 from both sides
b=11
The number of birds = 11